What is the difference between grep -e and grep -E option?
I am trying to understand the difference between grep -e and grep -E. Now from grep manpage I got:-E, --extended-regexp. Interpret PATTERN as an extended regular expression (see below).-e PATTERN, --regexp=PATTERN. Use PATTERN as the pattern; useful to protect patterns beginning with - The above explanation does not make sense for me.
How do I recursively grep all directories and subdirectories?
2010年1月1日 · Recursive grep is, of course, still preferable if available, but there's little reason to avoid the xargs recipe (do use -H for the grep to avoid the final invocation of grep getting passed only a single filename, though).
linux - What is the point of "grep -q" - Stack Overflow
2019年5月16日 · Here's an example of grep -q: scanning the output of a command for a particular value, then performing an action if the value is found: if docker context ls | grep -q dm-manager; then docker context rm dm-manager fi If the list of docker contexts contains dm-manager then remove docker context dm-manager.
What's the difference between grep -r and -R - Stack Overflow
2014年3月31日 · grep -r foobar . will only grep the files inside this directory, grep -r foobar foo will grep the files in the parent directory (..) (following the symlink given as an argument), grep -R foobar . will also grep the files in the parent directory (following the symlink not given as an argument but found while traversing the current directory).
regex - Using the star sign in grep - Stack Overflow
2016年7月6日 · grep '*abc*' file2 This one return *abc, because there is a * in the front, it matches the pattern *abc*. (3) grep '*abc*' file3 This one return *abcc because there is a * in the front and 2 c at the tail. so it matches the pattern *abc* (4) grep '.*abc.*' file1 This one return abc because .* indicate 0 or more repetition of any character.
shell - Exact grep -f command in Linux - Stack Overflow
2010年2月3日 · grep -x -f A.txt B.txt EDIT: If you don't want grep's regex capabilities and need to treat search pattern as fixed-strings then use -F switch as: grep -xF -f A.txt B.txt -x, --line-regexp Only input lines selected against an entire fixed string or …
Regex (grep) for multi-line search needed - Stack Overflow
2010年9月15日 · Without the need to install the grep variant pcregrep, you can do a multiline search with grep. $ grep -Pzo "(?s)^(\s*)\N*main.*?{.*?^\1}" *.c Explanation:-P activate perl-regexp for grep (a powerful extension of regular expressions)-z Treat the input as a set of lines, each terminated by a zero byte (the ASCII NUL character) instead of a ...
grepping using the result of previous grep - Stack Overflow
2015年9月20日 · I have found this problem more often while reducing the search scope through many searches (applying filters to the previous grep results). Trying to find general answer: Generate a list with the result of the first grep: grep pattern | awk -F':' '{print $1}' Second grep into the list of files like here. xargs grep -i pattern
How can I use grep to find a word inside a folder?
2010年11月8日 · grep -nr 'yourString*' . The dot at the end searches the current directory. Meaning for each parameter:-n Show relative line number in the file 'yourString*' String for search, followed by a wildcard character -r Recursively search subdirectories listed .
grep -P no longer works. How can I rewrite my searches?
2013年5月21日 · If your scripts are for your use only, you can install grep from homebrew-core using brew: brew install grep Then it's available as ggrep (GNU grep). it doesn't replaces the system grep (you need to put the installed grep before the system one on the PATH). The version installed by brew includes the -P option, so you don't need to change your ...